What’s the Best Temperature for a Tankless Water Heater?

By Danika | June 23, 2022

What’s the Best Temperature for a Tankless Water Heater?

temperature setting on water heater

If you’ve recently acquired a new tankless water heater you may not be as familiar with them as the older traditional tank heaters. Is there a major difference between the standard tank and tankless water heaters? If so, what’s the best temperature for a tankless water heater?

Before we get into the details on why let’s cut straight to the chase to answer your question:

The recommended temperature setting from the Consumer Product Safety Commission for a tank and tankless water heaters is 120 degrees. 

Tankless water heater temperature settings are the same as standard tank water heaters
Rheem tankless water heaters

The difference between a tank and tankless water heaters

As the name suggests a tank-less water heater does not store water in a tank. A tankless water heater produces hot water on demand. Tankless models pull water right from the source, heating it to the set temperature as it is drawn through the heater. 

This ensures that you’ll always have hot water when you want it, no matter how many family members beat you to the shower. 

Standard water heaters store the hot water in a holding tank. When you turn on hot water, it is drawn from this tank. This means that there is always hot water kept waiting, ready to be drawn from at the temperature you set the tank to be at. 

Standard tank water heater powered by electricity
We replace and repair electric tank water heaters

Which heater is more efficient?

Tankless water heaters are more energy-efficient. Instead of coming on periodically to keep the water in the tank at the set temperature, the tankless heater only heats the water when somebody is using it. If nobody is home all day, your tankless heater won’t come on until you come home and turn on the dishwasher or jump in the shower. 

For comparison, with a tankless heater, about 82 cents of every dollar spent on its energy heats the water. Standard heaters only use about 60 cents of every dollar to heat the water. You can certainly see the difference.

What’s the ideal tankless water heater temperature?

If you’re not familiar with a tankless heater, you may wonder what temperature setting you should use, and if it’s different than that used with a standard heater. Actually, they are the same

The recommended temperature setting from the Consumer Product Safety Commission for a tank and tankless water heaters is 120 degrees. 

The 120-degree setting is especially important for households with elderly occupants or small children to prevent burns. A child can receive second or third-degree burns from just two seconds of exposure to 140-degree water. Some water heaters leave the factory with the temperature set at 140 degrees, so it’s a good idea to check out the setting when you get a new one.

Are 130 degrees too hot for any water heater?

Some people like hotter water, but if so, 130 degrees is as high as you should go for the shower. You’re just wasting money setting it any higher and risking a burn! 

There are several factors that play into the temperature setting. The type of piping you have in your home, or how the water is heated (gas or electricity) makes no difference as far as the temperature setting.

If you don’t have small children or elderly people in your household, but you do have someone with respiratory disease or a suppressed immune system, you should probably aim for a temperature of 130 to 140 degrees to ensure that no bacteria gets into the water.

People who have dishwashers that don’t have a setting to pre-heat the water inside often opt to use a higher temperature setting.

What’s the minimum shower temperature?

Most skin specialists will recommend showering in water with a temperature between 98°-101° F with a maximum of 104°. So what does this mean in terms of setting your water heater temperature?

While most recommend that 120 is the best temperature for a tankless water heater, don’t fall for the idea that setting it lower than 120 degrees will save money. You can save three to five percent on your energy bill for every ten degrees you decrease the water heater temperature. However, it can also cause problems in the long run. Any setting lower than 120 degrees may allow bacteria to grow in the tank and get into the water.

How to increase the water temperature in the shower

Many water heaters come with a temperature settings dial that doesn’t have temperature marks, but instead, its setting marks are labeled Low, Hot, A, B, C, and Very Hot. With this kind of dial, the settings usually mean:

  • Low (or Warm) = 80-90°
  • Hot (or triangle symbol) = 120°
  • A = 130°
  • B = 140°
  • C = 150°
  • Very Hot = 160°

Always double-check your owner’s manual should about what these letters stand for on your particular model.

what's the best temperature for a tankless water heater? This dial shows low, hot, A, B, C and very hot

Tips to set the optimal temperature on your water heater

Before you start adjusting your water heater’s temperature setting, however, you should check your water temp to see just what you’re getting. A good way is to run the hot water from a faucet near the water heater for a few minutes, then collect it in a container. Put in a cooking thermometer and leave it in the water for a few minutes. 

A handheld temperature gun aimed at a good-sized stream of running water can also give you good results. If you don’t like what you see, then you can adjust your heater’s temperature.

What is considered a safe water temperature for a bath?

It comes down to personal preference but if you like your bath like a hot tub, then you want the temperature to be above 98 degrees. The temperature on most hot tubs is set to be between 100 and 104 degrees. Adults can handle higher temperatures but it’s not recommended to stay in the water for extended periods of time. 

Set it and forget it!

A water heater is probably the one appliance you have in your home that you think about least even though you use it regularly every day. Discovering just what temperature the water is when it runs out of your faucet, then adjusting it if necessary to keep your family safe and comfortable. Hopefully, you won’t need to trouble yourself with adjustments for a long time. 

By finding the best temperature for your water heater, you can also be sure that you aren’t sending money literally down the drain by having the water heated more than you need. Once you got it figured out, you can let it sit there and do its thing for the next decade or so.

If you have any questions, comments, or need an over-the-phone consultation about your water heater-call Danika. We’re here for you 24 hours a day, 7 days a week.

For more info, read our article on “7 Signs You Need A New Water Heater

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